Chapter 6 - z-coordinate

All the classes that extend from Feature (PV, View, Prop, Act, Ego) have a z coordinate. This can be used to 'elevate' the object above or below the ground. The same could be accomplished with the y coordinate, but change this will affect the motion classes applied to the actor, and it will also change the priority of the actor.

Walking on elevated ground.

Suppose we have a section of elevated ground on which the ego can walk.� We could draw a particular control color over this elevated ground in the pic.

Supposing ctlGREEN was the control color:
Code:

   (method (doit)
       (super:doit())

       (if (& (send gEgo:onControl()) ctlGREEN)
           (send gEgo:z(3)) // Ego is elevated by 3 pixels.
       )(else
           (send gEgo:z(0)) // Ego is back to normal
       )
   )

Incidentally, changing the z-coordinate has the same effect as changing the Y coordinate of a view's 'placement' (these are the X and Y coordinates of the view in SCI Studio's view editor). However, the placement of a view is fixed, while the z-coordinate can be changed in code.

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